This research proposal aims at understanding the role of Kruppel-like zinc-finger transcription factors KLF4 and KLF5, two of the most abundant transcription factors in the mouse cornea, in regulating the normal development and maintenance of mature cornea. Early lethality of KLF4 and KLF5 knockout mice is an impediment to study their involvement in regulating the normal development of cornea, which continues up to 6 weeks after birth. Conditional disruption of KLF4 and KLF5 genes is proposed here to overcome this problem. Effects of these conditional mutations on embryonic development of cornea and post-natal stratification of corneal epithelial cells will be studied by histology. Mature cornea from these conditional mutants will be compared with that of wild type littermates, with respect to transparency, morphology, and wound healing ability. Their gene expression patterns will be compared with that of wild type mice by microarrays and differences confirmed by quantitative PCR and in situ hybridizations. The involvement of KLF4 and KLF5 in regulating the promoters of identified target genes of interest will be analyzed in cultured cells. Studies proposed here will provide information of fundamental importance on regulation of gene expression during normal development and maintenance of cornea, and provide a solid foundation for further research in this relatively understudied field of gene regulation in cornea. Specific Aims: 1. To study the effect of conditional disruption of KLF4 and KLF5 genes in the mouse eye on the development and maintenance of mature cornea. 2. To identify the target genes for KLF4 and KLF5 in the developing cornea. 3. To study the involvement of KLF4 and KLF5 in regulation of expression of selected genes in the cornea.